Tom Lane wrote: > "Simon Riggs" <[EMAIL PROTECTED]> writes: >> Any page written during a backup has a backup block that would not be >> removable by Koichi's tool, so yes, you'd still be safe. > > How does it know not to do that? > > regards, tom lane > > ---------------------------(end of broadcast)--------------------------- > TIP 5: don't forget to increase your free space map settings >
XLogInsert( ) already has a logic to determine if inserting WAL record is between pg_start_backup and pg_stop_backup. Currently it is used to remove full_page_writes when full_page_writes=off. We can use this to mark WAL records. We have one bit not used in WAL record header, the last bit of xl_info, where upper four bits are used to indicate the resource manager and three of the rest are used to indicate number of full page writes included in the record. In my proposal, this unused bit is used to mark that full page writes must not be removed at offline optimization by pg_compresslog. Regards; -- ------ Koichi Suzuki -- Koichi Suzuki ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
